I am not sure I understood your questions. If the PlayBook has 4G or 4G Lte and a data plan, you would not need to use Bridge on the handset. As far as I know the 4G/LTE PlayBooks are not available in the US yet.

The Bridge app uses Bluetooth. If your phone has 4G Lte, then your PlayBook should be faster online when bridged. None of the current BlackBerry phones have 4G/LTE but the new BlackBerry 10 phones will have it.